It was something of a Diana moment: an outpouring of grief and emotion that was unexpected as the death itself. The death on 9 January of American Jewish singer-songwriter Debbie Friedman, at the age of 59, has touched whole swaths of the English-speaking progressive Jewish world: the web buzzes with tributes and 7,000 people watched a webcast of her memorial service.

Of course there is a massive disparity between Friedman's high profile and reputation in the Jewish world and her almost complete obscurity outside it. But her death provides a good opportunity to reflect on the possibilities and limitations inherent in the idea of a religious popular music.

Heavily influenced by 1960s American folk music, Friedman's work has strong echoes of Joan Baez and Peter, Paul and Mary; sincere, acoustic guitar-led invocations of peace, spirituality and healing. Singing in both Hebrew and English, Friedman composed original works, new settings of traditional prayers and children's songs. Her career developed within US Reform Judaism's summer camp system and her music remains ubiquitous within English-speaking non-orthodox youth movements worldwide. It has also had a profound impact on Reform liturgy, with Friedman's tunes ubiquitous in many Reform communities. Friedman began a trend towards spirituality and participation in Reform Jewish ritual, stimulated by her own indefatigable work as a highly charismatic song-leader.

The genuine grief demonstrated at Friedman's death was in part a function of her own warmth and modesty as a human being – which I can attest to, having met her twice – and also a result of the incredible importance that her music plays in many non-orthodox Jews' spiritual lives. It is difficult therefore to be critical of her music without trampling over these very raw feelings.

Yet it is hard to ignore the fact that, in many respects, Friedman's music appears unremarkable, dated and even naive. This is achingly sincere "happy clappy" music, sneered at by hipsters and the more traditionally-minded alike. It is hard to ignore the similarities between Friedman's work and contemporary Christian music. And it is hard to ignore the fact that, while the infusion of popular music into contemporary Christian and Jewish worship has endowed these venerable religions with a new energy and enthusiasm, for those who are not adherents this is some of the most reviled music in the world today. There is a poignant irony in that the new forms of worship, intended to invite participation and break down barriers, put off as many as it attracts.

It is important therefore to remind ourselves of the radical aspects of Friedman's work and also of the wider contemporary religious music scene. Friedman began writing and leading songs at a time, the early 1970s, when women were only just beginning to assume rabbinic positions in the Reform Jewish world. Her work helped to stimulate the move towards egalitarian worship. She is the first woman in Jewish history to have had a major impact on Jewish liturgy – and she was a lesbian to boot (how "out" she was is a matter of debate). Friedman taught Reform Jews to take ownership of worship, to see liturgy not just as something done by a remote priest-like leader (a common fault in decorum-obsessed non-orthodox Judaism); in short she helped to democratise at least one stream of Judaism.

The same is true of contemporary Christian worship music. Although it is often associated today with the evangelical right, from the hippie-influenced "Jesus people" of the 1960s and 1970s to the open-minded diversity of the Greenbelt festival today, new forms of popular music-influenced Christian worship music have, at their best, been associated with a radical Christianity that eschews hierarchies.

It is this echo of radicalism that I hear in Friedman's work that leads me to mourn her, even if her music does not inspire me personally.

In the end though, like any revolution, the new forms of worship music that were born in the 1960s, have become established and lost much of their potency. In being tied to a music that came out of a very specific place and time, the new forms of worship pioneered by Friedman and others like her, run the very real risk of becoming archaic in what is in Jewish terms a very short space of time.

For me, it is the longer traditions of Jewish worship, particularly those practiced by orthodox Jews, that inspire and that may be less susceptible to being dated and subject to the scorn of the hipsters. It may be though, that in the course of time, Friedman's work will become a venerable part of liturgy and that Jews will forget its historical origins – this is, after all, how traditions are established.